Field of the Invention
The present invention relates to an exposure apparatus and a device manufacturing method using the same.
Description of the Related Art
An exposure apparatus is configured to transfer a pattern of an original (reticle or mask) onto a photosensitive substrate (e.g., wafer, glass plate, and the like, where the surface thereof is coated with a resist layer) via a projection optical system in a lithography process of a manufacturing process for a semiconductor device, a liquid crystal display device, and the like. The exposure apparatus typically includes an original stage that movably holds an original. Examples of such a mechanism for holding an original onto the original stage include a mechanism utilizing a vacuum adsorption force or an electrostatic attraction force, a mechanism utilizing an actuator for generating a pressing force, or the like. In any one of these mechanisms, it is preferable that a holding surface for holding an original is the lower surface in the direction of gravity from the viewpoint of preventing an original from being dropped off by gravity.
Since the original has a circuit pattern formed thereon by maximally utilizing an inner effective area and the entire surface of the circuit pattern is irradiated with exposure light, the original is typically held by a rectangular holding frame using the outer peripheral portion of the original as a holding surface. Here, when exposure light is irradiated onto the original, a portion of exposure light is absorbed into the circuit pattern, and thus, light energy is converted into heat energy. The heat energy causes a thermal deformation of the original and is diffused into the surrounding environment through solid heat transfer via the original itself and the holding frame, convection heat transfer via the surrounding air, and radiative heat transfer. For example, gas retaining in an enclosed space between the original and the holding frame is heated by these types of heat transfer. Consequently, the gas may reduce the measurement accuracy of an alignment measurement system for performing the positioning of the original or may generate fluctuations in light directed from the original toward the projection optical system. In addition, thermal deformation of the original itself may also directly affect imaging performance. Accordingly, Japanese Patent Laid-Open No. 2002-353127 discloses an exposure apparatus that improves the recovery rate of heat accumulated in an original (reticle) by providing a flow passage for gas near the original to thereby reduce disturbances in the surrounding environment. In the exposure apparatus, thermal deformation of the original is suppressed by forcibly introducing temperature control fluid into a space between an original and an anti-adhesion film (pellicle) provided thereon. At this time, the temperature control fluid is introduced from piping directly disposed on a fixed frame (pellicle frame) for the anti-adhesion film.
However, the piping for introducing the temperature control fluid disclosed in Japanese Patent Laid-Open No. 2002-353127 is physically coupled to an original. Thus, vibration of the piping itself due to introduction of the temperature control fluid or external vibration transmitted via the piping are transmitted to the original. For example, if vibration to be transmitted to the original has a frequency from a few hundreds to a few thousands Hz, Moving Standard Deviation (MSD) which is the index affecting resolution may be deteriorated. Fluid vibration or pressure fluctuation caused by non-uniformity between the supply amount and the recovery amount of the temperature control fluid adversely affects an original, resulting in possible breakage of an anti-adhesion film. In addition, the anti-adhesion film is originally intended to prevent particles from being deposited on the original. However, deposition of particles may be promoted by introducing the temperature control fluid at the inner side of the anti-adhesion film. Furthermore, from the viewpoint of the piping implementation, the laying of the piping near the original stage becomes complicated, resulting in an increase in a mechanical load on the original stage. If such a configuration is applied, the piping must be detached during the exchange of the original, not only resulting in a redundancy of an original conveyance mechanism but also causing the occurrence of particles.